Powder grain baffle for recoilless rifle



Nov. 14, 1961 c w. MUSSER 3,008,378

POWDER GRAIN BAFFLE FOR RECOILLESS RIFLE Filed April 28, 1960 INVENTOR. c WALTON MUSSER y j f-imama ATTORNEYS:

its

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to recoilless rifles and more especially to an improved rifle which is constructed to minimize the unburned powder discharged from its venturi upon the firing of a cartridge.

As heretofore constructed, recoilless rifles are subject to the Objection that they discharge too much unburned powder from their venturi. This renders the rifle less efiicient than it could be and is a hazard to personnel. The present invention minimizes this difiiculty by the provision of an improved arrangement of bafiles within the chamber of the rifle.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims.

The single figure of the drawing is a partial view of the chamber of a recoilless rifle such as that disclosed by Patent No. 2,741,160 of C Walton Musser. Threaded into the breech end of the chamber it) is a venturi ring 11 which is adapted to receive a cartridge 12. A breech block 13 is operated by a mechanism similar to that described in the aforementioned patent into and out of engagement with the ring 11 and the cartridge 12. The breech block 13 has four lugs which form a continuation of the inner walls of the venturi when the breech block is in its closed position.

Starting with this old structure, the present invention provides an arrangement whereby the powder carried by the gas incident to the firing of the cartridge 12 is constrained to a path which effects more complete burning of the powder before the 'gas is ejected from the venturi.

This arrangement includes (1) an outer bathe 14 which is fixed between the muzzle end of the ring 11 and a shoulder on the inner periphery of the chamber 10 and (2) an inner bafile 15 which has its breech end threaded into the ring 11. The inner bafile 15 is ofiset to form an outwardly extending ridge 16 slightly in advance of the outer baflie 14.

The big difference between the recoilless rifles that have been standardized in the United States and those that have been more or less unsuccessful in the foreign countries is in the type of cartridge case used. In the American recoilless rifles, a perforated cartridge case has been used which permits the gases to expand radially into the chamber and then change their direction and flow axially out through the nozzle. In the unsuccessful foreign rifles, there is no radial expansion, and the gases flow directly to the rear through the nozzle. As a consequence, a larger and more uncontrollable amount of unburnt powder is used in the foreign rifles.

Since the powder gases are generated from the powder grains in a matter of milliseconds, anything that can be done to delay them from flowing through the nozzle will help in preventing unburnt powder grains from being blown out the rear of the nozzle. Hence, the radial expansion, with a change of direction to an axial direc- Patented Nov. 14, 1851 tion, materially assists in obtaining this result. However, close inspection of a recoilless rifle, such as that disclosed by Patent No. 2,741,160 shows that a given powder grain has a considerably different distance to travel depending upon which end of the cartridge case it is flowing from. If it is flowing from the rear of the cartridge case, it has only to travel a matter of an inch or so before it is out of the nozzle. If it is flowing from the front part of the cartridge case, it may have to travel as much as several feet, depending upon the actual size of the weapon in question. By the introduction of the baffle 15, it becomes evident that the powder grain that formerly had the least distance to travel is in that part of the case which is close to the end of this baflle. For this powder grain which formerly had the least distance to travel, it now must move approximately half the length of the cartridge case or the full length of the bathe before it can go out of the nozzle. All other cartridge grains, separated in front of or to the rear of this point, would have to travel a farther distance. As a consequence, the bafiie can then be considered as a means of increasing the travel of the powder grain closest to the nozzle. Since travel at any speed requires time, this gives the powder grain a chance to more fully burn before it gets to the nozzle; so it is not only a question of bafiling the powder gases, but it is also a question of increasing the length of travel so as to increase the time before nozzle exit.

The rearward baffle 14 is also so shaped that in the annular space around its lip there has been left a sufficient volume to trap solid particles which are streaming rearwardly along the wall of the chamber.

The angle of the front baffle l5 and its annular clearance with the tapered wall of the chamber, are intended to direct the moving gases along the wall of the chamber. As they approach the lip of the rear baflle 14, they must rapidly change their direction so as to move into the opening that is communicating with the nozzles. Since the gases can change their direction more easily than the solid powder particles, at least some of these solid powder particles will be blown into the annular space or volume between the baflle 14 and the chamber wall. This provides an additional time delay.

I claim:

The combination of a recoilless rifle, and a cartridge having a perforated case and adapted to be fired by said rifle, said rifle including a chamber terminating in a plurality of venturi formed in part by a venturi ring fixed to the end of said chamber and in part by the lugs of a breech block movable into and out of engagement with said ring, a relatively long inner baffle fixed to said ring and extending into said chamber, and a relatively short baffle supported between said ring and an inner shoulder of said chamber, said inner baflie having a rearward section gradually increasing in diameter from its rearward end, an intermediate section abruptly increasing in diameter from its rearward end and a forward section parallel with the wall of said chamber whereby a forward axial movement is imparted to the gas and solid particles ejected from the rear section of said case upon the firing of said cartridge, and said short baffle having a lip extending into said chamber and spaced from the wall thereof whereby the solid particles streaming rearwardly along the wall of said chamber are trapped between said wall and said lip.

Hickman May 27, 1952 Leduc Apr. 2, 1957 

